HOT TOPICS:

The U.S. Department of Homeland Security has customized its Predator drones, originally built for overseas military operations, to carry out at-home surveillance tasks that have civil libertarians worried: identifying civilians carrying guns and tracking their cell phones, government documents show.

The documents provide more details about the surveillance capabilities of the department's unmanned Predator B drones, which are primarily used to patrol the United States' northern and southern borders but have been pressed into service on behalf of a growing number of law enforcement agencies including the FBI, the Secret Service, the Texas Rangers, and local police.

Homeland Security's specifications for its drones, built by San Diego-based General Atomics Aeronautical Systems, say they "shall be capable of identifying a standing human being at night as likely armed or not," meaning carrying a shotgun or rifle. They also specify "signals interception" technology that can capture communications in the frequency ranges used by mobile phones, and "direction finding" technology that can identify the locations of mobile devices or two-way radios.